PEMFC System Research Articles

Integration and optimization for a PEMFC and PSA oxygen production combined system

In this research, a new type of high-temperature proton exchange membrane fuel cell and pressure swing adsorption (PEMFC-PSA) oxygen generation integrated system is proposed. The thermodynamic model of the integrated system of PEMFC-PSA oxygen production was established. The effects of oxygen concentration, temperature, oxygen flow rate and pressure on the efficiency and net power of the PEMFC-PSA integrated system are studied. The results show that as the oxygen concentration increases, the net power of the new integrated system increases to 85% of the oxygen concentration, which corresponds to the maximum net power value of 101 W, and then decreases. Therefore, the oxygen concentration fed to the system is 85% to produce the maximum net power, and the system should operate under air conditions for maximum efficiency. With the increased operating temperature, pressure and oxygen inlet speed of the system, the maximum net power and maximum efficiency of the new integrated system are achieved.

Optimal Allocation of a Hybrid Wind Energy-Fuel Cell System Using Different Optimization Techniques in the Egyptian Distribution Network

This paper presents an optimal proposed allocating procedure for hybrid wind energy combined with proton exchange membrane fuel cell (WE/PEMFC) system to improve the operation performance of the electrical distribution system (EDS). Egypt has an excellent wind regime with wind speeds of about 10 m/s at many areas. The disadvantage of wind energy is its seasonal variations. So, if wind power is to supply a significant portion of the demand, either backup power or electrical energy storage (EES) system is needed to ensure that loads will be supplied in reliable way. So, the hybrid WE/PEMFC system is designed to completely supply a part of the Egyptian distribution system, in attempt to isolate it from the grid. However, the optimal allocation of the hybrid units is obtained, in order to enhance their benefits in the distribution networks. The critical buses that are necessary to install the hybrid WE/ PEMFC system, are chosen using sensitivity analysis. Then, the binary Crow search algorithm (BCSA), discrete Jaya algorithm (DJA) and binary particle swarm optimization (BPSO) techniques are proposed to determine the optimal operation of power systems using single and multi-objective functions (SOF/MOF). Then, the results of the three optimization techniques are compared with each other. Three sensitivity factors are employed in this paper, which are voltage sensitivity factor (VSF), active losses sensitivity factor (ALSF) and reactive losses sensitivity factor (RLSF). The effects of the sensitivity factors (SFs) on the SOF/MOF are studied. The improvement of voltage profile and minimizing active and reactive power losses of the EDS are considered as objective functions. Backward/forward sweep (BFS) method is used for the load flow calculations. The system load demand is predicted up to year 2022 for Mersi-Matrouh City as a part of Egyptian distribution network, and the design of the hybrid WE/PEMFC system is applied. The PEMFC system is designed considering simplified mathematical expressions. The economics of operation of both WE and PEMFC system are also presented. The results prove the capability of the proposed procedure to find the optimal allocation for the hybrid WE/PEMFC system to improve the system voltage profile and to minimize both active and reactive power losses for the EDS of Mersi-Matrough City.

Predictive Maximum Power Point Tracking for Proton Exchange Membrane Fuel Cell System

This project aims to design a predictive maximum power point tracking (MPPT) for a proton exchange membrane fuel cell system (PEMFC). This predictive MPPT includes the predictive control algorithm of a DC-DC boost converter in the fully functional mathematical modeling of the PEMFC system. The DC-DC boost converter is controlled by the MPPT algorithm and regulates the voltage of the PEMFC to extract the maximum output power. All simulations were performed using MATLAB software to show the power characteristics extracted from the PEMFC system. As a result, the newly designed predictive MPPT algorithm has a fast-tracking of maximum power point (MPP) for different fuel cell (FC) parameters. It is confirmed that the proposed MPPT technique exhibits fast tracking of the MPP locus, outstanding accuracy, and robustness with respect to environmental changes. Furthermore, its MPP tracking time is at least five times faster than that of the particle swarm optimizer with the proportional-integral-derivative controller method.

Application of an Ageing Model to a Hydrogen-Fuelled PEM Fuel Cell

Hydrogen is one of the most promising energy vectors for achieving the decarbonization of the propulsion systems market. Polymer Electrolyte Membrane Fuel Cell system (PEMFCs) stand out in this panorama, thanks to reduced activation times and low temperatures of use, easily adapting to the needs of the sector. In this paper, a multi-phase, multi-component and non-isothermal 3D-CFD model is proposed to simulate the effects of PEMFC ageing, limiting the system durability due to slow membrane corrosion and loss of material performance and properties degradation, resulting in a reduced current density under equal voltage. The model is applied both in 1D and 3D frameworks implementing a validated model from literature, allowing to estimate the useful life of the cell as a function of parameters such as the degradation rate and the crossover rate. Simulations are carried out at different membrane thicknesses and for different membrane conductivities, using a hydrogen-fuelled serpentine-type PEM fuel cell. The study relevance lies in the possibility to investigate the critical aspects limiting PEMFC system durability, as well as the optimal conditions of use, and it allows to identify corrective design actions.

Study of the impact of reactants utilization on the performance of PEMFC commercial stacks by impedance spectroscopy

Reactants utilization is a key stake for a PEMFC system: a too low utilization leads to a waste of reactant but a too high utilization may result in a detrimental starvation. To study these impacts, two commercial stacks were characterised by impedance spectroscopy under different hydrogen and oxygen utilizations (from nominal conditions to quasi-starvation). One was fresh while the other was operated on-field during 10,000 h. This study shows that the two capacitive loops in the lowest frequency range (1 Hz and below) correspond respectively to oxygen and hydrogen mass transfer limitations: the limiting reactant can be clearly identified from the impacted frequencies. The size of these loops was increased by up to 30% when the cell operated at high reactant utilizations. These results could therefore pave the way to the development of algorithms able to estimate the degree of starvation of some cells.

Automotive Cold Start of a PEMFC System by Using a Methanol Solution as Antifreeze

Proton exchange membrane fuel cell vehicles are highly competitive due to their zero emissions, high efficiency and power density, quick response, low refuelling time and great autonomy. However, the lack of a sufficient hydrogen infrastructure and their required startup ability and durability at extreme winter conditions are limiting factors in their commercialisation. At subzero temperatures, the produced water during operation as well as the remained water in the cells after shutdown will freeze, hindering the cold start and causing several damages (e.g. cracks, pinholes, catalyst delamination or loss of electrochemical surface area). Commonly, the fuel cell system is purged with dried gases during shutdown to avoid that it freezes during the cold storage. Even though the dry gas purge methods have been extensively studied, thus reducing the degradation due to F/T cycles, there are still remaining unsolved issues, especially at very low temperatures. An alternative method that can mitigate this degradation and hence lower the temperature is the use of an antifreeze solution during the cold storage. Yet, it has been only tested in a single cell1. These results were quite promising, as the use of the antifreeze strongly diminished the degradation because of subzero temperatures and it was possible starting at -10°C. But they showed fairly poor cold start ability, since the residual methanol decreased the power density during the cold start. Therefore, the use of an antifreeze solution for a cold start should be further investigated in a stack.The aim of this study is to prove the cold start capability of a PEMFC system by using a methanol solution as antifreeze. For that, several cold starts at -10°C were carried out with a 4 kW commercial stack, a 25 vol% methanol solution to ensure no ice formation at -10°C and following next test protocol. A conditioning test and a polarization curve were conducted at room temperature. Then, the shutdown procedure, which involved soaking the stack with the methanol solution, was carried out before cooling down the system to -10°C. Following the cold storage, the antifreeze was removed from the stack and the cold start test was run. Finally, another polarization curve at room temperature was carried out. The cold start system ability with the antifreeze was compared with previous cold starts, which only used a dry gas purge method.All cold starts with antifreeze were successfully, thus proving the cold start capability of the PEMFC system by using the methanol solution. Indeed, they did not take longer than with the dry gas purge method. During the cold start the current generation did not decrease, which shows that the produced water did not freeze. Moreover, polarisation curves corroborated no performance losses after every cold start. These results are in concordance with those obtained at single cell level, as in both cases the antifreeze avoided ice formation during the cold storage. This significantly improvement with regard to the above results obtained with a single cell, is due to the ability of the stack to generate much more heat power and to minimize thermal losses, warming up the stack faster than a single cell.The obtained results allow confirming that a self-start of an automotive PEMFC system at subzero temperatures by using antifreeze solution is possible. This alternative method avoids ice formation during the cold storage, which reduces the degradation due to freezing and enables starting at lower temperatures. The decline in degradation increases the stack lifetime, thus can be achieved the strict automotive sector demands. The advantages of the antifreeze for automotive cold start can be used for others mobile applications too, such as trucks, trains, maritime or aircraft. In the future, cold starts with the antifreeze should be further investigated, and at temperatures down to -40°C.1. F. Knorr, D. Garcia, J. Schirmer, P. Gazdizcki, and KA. Friedrich. Appl. Energy, 238, 1 (2019).

NO/NO2 Contamination of HT-PEM Fuel Cells – A Degradation Study with Evaluation of Regeneration Strategies

In view of a sustainable energy supply, polymer electrolyte membrane fuel cell technology is used in several stationary and mobile application fields of power generation. High temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are operated at increased temperatures of around 160 °C to achieve a simplified water and heat management and to enhance the tolerable CO concentration in fuels. HT-PEMFCs are especially attractive in combination with methanol reforming in combined heat and power systems for auxiliary power units and further application fields. [1]Air pollution is a world-wide problem, whereby especially in urban areas ambient air contains nitrogen oxides (NOx) mainly originating from traffic. It has been shown in several studies that such NOx contamination affects the performance of low temperature PEMFC systems. [2] NO/NO2 enters the cathode through the supply with ambient air and reversibly adsorbs onto the platinum surface leading to catalytic deactivation. Immediate regeneration of low temperature PEM cells is possible by supplying clean air. [3] Although the HT-PEMFC system accounts for an enhanced tolerance towards CO contamination, NO/NO2 has a significant impact on its cell performance. On one hand, cell degradation is not completely understood yet, and on other hand, cell regeneration is not given by simple switching to clean air as in case of LT-PEMFCs. [4]For this purpose, systematic NOx contamination of commercially available HT-PEM single cells was carried out followed by analysing performance changes in dependence of several cell operational modes. First, the cell start-up was performed for two days at 160 °C and constant load of 0.3 A cm-2. Second, a controlled contamination using 10 ppm NO or NO2 inside the cathode air stream was applied. Last, after significant decrease of the voltage different cell operation modes were applied and tested as regeneration strategies, while the voltage change was continuously monitored. Cell operation under open circuit voltage (OCV), N2/N2 supply to both electrodes, cyclic voltammetry (CV up to 1.0, 1.2 and 1.5 VRHE) and an increased temperature of 180 °C were utilized. To evaluate the cause of voltage changes, the cells were electrochemically characterized using polarization curves, electrochemical impedance spectroscopy, cyclic voltammetry and linear sweep voltammetry at begin of test, after operation with contaminated air and after switching to the defined cell modes.Figure 1a) shows the voltage over time of cell break-in followed by operation under NO2 contamination resulting in a significant degradation of -364 µV h-1. Figure 1b) shows the voltage monitored during applying the different cell modes after cell contamination. NO2 is verified to have a dramatic impact on the HT-PEMFC without any regenerating effect by any of the cell modes. In conclusion, this study demonstrates the strong impact of NO/NO2 on HT-PEMFC systems and furthermore points out the difficulty to regenerate the cell after contamination. This is an important evidence for industry that less a suitable cell operation strategy and more a system engineering approach in view of appropriate filter systems is one possible way of solving the NOx contamination issue.[1] R. E. Rosli, A. B. Sulong, W. R. W. Daud, M. A. Zulkifley, T. Husaini, M. I. Rosli, E. H. Majlan, M. A. Haque, Int. J. Hydrogen Energy 2017, 42, 9293-9314.[2] X. Cheng, Z. Shi, N. Glass, L. Zhang, J. Zhang, D. Song, Z.-S. Liu, H. Wang, J. Shen, J. Power Sources 2007, 165, 739-756.[3] A. Talke, U. Misz, G. Konrad, A. Heinzel, J. Electrochem. Soc. 2018, 165, F3111-F3117.[4] Final Project Report „HT-Kathodenluft“ 2016. Figure 1: Voltage and current density of cell break-in followed by operation under NO2 contamination (a) and voltage monitoring during applying different cell modes (b). Figure 1

Temperature Control for a Proton-Exchange Membrane Fuel Cell System with Unknown Dynamic Compensations

Numerous control strategies of temperature regulation have been carried out for proton-exchange membrane fuel cell systems including a cooling fan in order to ensure operation at the desired condition and extend the lifetime of the fuel cell stack. However, most existing control strategies are developed without considering the efficiency limitation of the cooling system such that the cooling fan may be unable to eliminate the additional heat. Moreover, there are unknown modelling errors, external disturbance and noise during modelling and experiment processes for fuel cells. Due to those unknown dynamics, the conventional control strategies may fail to achieve the expectant results. To address this issue, an alternative control strategy is proposed in this paper, which consists of a composite proportional-integral (PI) controller with an unknown system dynamics estimator. First, the control strategy is developed by reducing the temperature of input air through the humidifier and simultaneously increasing the mass flow of air in order to eliminate the excess heat that a cooling fan cannot remove. Moreover, an unknown system dynamics estimator is proposed in order to compensate the effect of the unknown dynamics. The construction of the estimator is designed through finding an invariant manifold which implies the relation between known variables and the unknown manifold. The invariant manifold is derived by applying a simple low-pass filter to the system which is beneficial to avoid the requirement of the unmeasurable state derivative. Furthermore, the proposed estimator is easily merged into the proposed PI control strategy and ensures the exponential convergence of estimated errors. Besides, the estimator is further modified such that the derivative of the desired temperature is not required in the controller. Finally, numerical simulations of the PEMFC system are provided and the results illustrate the efficacy of the proposed control strategy.

A Double Dual Boost Converter with Switching Ripple Cancellation for PEMFC Systems

This paper presents a current-based control for a proton-exchange membrane fuel cell using the so-called double dual boost topology. In particular, we introduce a discrete time controller that, in coordination with a particular selection of inductors and capacitors, minimizes the switching ripple at the input port (current ripple) and the output port (voltage ripple) of the double dual boost converter. This converter has a particular characteristic, in contrast to the classical interleaved boost topology, in the double dual boost, the phases of the converter can have different duty ratios. The freedom to choose the duty ration for each phase can be used to select the operative point in which the input current is equal to zero. However, if individual controllers are used for each branch of the converter, the equilibrium after a transient can differ from the minimum ripple operation point; the proposed scheme regulates the output voltage and, at the same time, ensures the equilibrium remains in the minimum ripple operation in steady state. In this way, the converter can mitigate the harmonic distortion on the current extracted from the proton-exchange membrane fuel cell, which is beneficial to improve the efficiency and lifetime of the cell, and on the output voltage delivered to an output direct current bus. The results of the experiment are presented to validate the principles of the proposed system.

Automotive Cold Start of a PEMFC System by Using a Methanol Solution as Antifreeze

The startup ability and durability at winter conditions has been a key issue for fuel cell vehicles. To reduce ice formation and to improve the cold start and lifetime of the PEMFC system, the remained water is commonly purged with dry gases at shutdown. This paper proposes an alternative cold storage method based on the use of a methanol solution as antifreeze. In order to study the cold start ability of a PEMFC system by using this method, cold start experiments at -10°C were performed with a 4 kW PEMFC stack. The results show that the stack can be successfully started at -10°C after being stored with the methanol solution and after these cold starts no performance degradation was observed. Furthermore, the use of the antifreeze method at shutdown may reduce its time and improve the energy efficiency of the system.

Development of a 240 kW PEMFC system model for a ship

Development of a 240 kW PEMFC system model for a ship

Development of online systematic condition assessment architecture for integrated PEMFC systems based on data-driven random matrix analysis

Due to complex configuration of high power integrated PEMFC systems, the associated systematic condition assessment is still a promising challenge. In this paper, an online systematic condition assessment architecture for high-power integrated PEMFC systems is put forward based on random matrix analysis. The proposed architecture consists of two cascaded procedures, which are the streaming formulation of random characteristic matrices and random matrix analysis based systematic condition assessment, respectively. Benefited from the signal cluster transformation by the fusion of model-driven and data-driven approaches, the residuals characterizing system abnormal can be extracted to formulate the streaming random matrices. On this basis, by recursive eigenpairs' updating of random covariance matrices, high-dimensional analysis can be conducted in real-time even with random tensor augmentation-based matrix dimension expansion, and the systematic condition assessment indicators can be derived. Taking temperature anomaly awareness as an example, detailed experiment results demonstrate that, the derived indicators are more sensitive to system anomaly than traditional threshold-based condition assessment method, and the online evaluation of the operation condition of integrated PEMFC systems can be achieved more effectively under the proposed systematic condition assessment architecture. Finally, a recommended online robust systematic condition assessment procedure with the fusion of multi-indicators is demonstrated. To our best knowledge, this paper represents the attempt to put random matrix analysis into the online systematic condition assessment of high-power integrated PEMFC systems for the first time.

Determination of fuel utilisation and recirculated gas composition in dead-ended PEMFC systems

This work presents a fundamental theory and methods for understanding the gas composition dynamics in PEMFC anode fuel supply compartments operated dead-ended with recirculation. The methods are applied to measurement data obtained from a PEMFC system operated with a 1 kW short stack.We show how fuel utilisation and stack efficiency, two key factors determining how well a fuel supply system performs, are coupled through the anode gas composition.The developed methods allow determination of the anode fuel supply molar balance, giving access to the membrane crossover rates and the extent of recirculated gas exchanged to fresh fuel during a purge. A methane tracer gas is also evaluated for estimating fuel impurity enrichment ratios.The above theory and methods may be applied in modelling and experimental research activities related to defining hydrogen fuel quality standards, as well as for developing more efficient and robust PEMFC system operation strategies.

Sulfonated graphene oxide as an inorganic filler in promoting the properties of a polybenzimidazole membrane as a high temperature proton exchange membrane

A commercial perfluorinated sulfonic acid (PFSA) membrane, Nafion, shows outstanding conductivity under conditions of a fully humidified surrounding. Nevertheless, the use of Nafion membranes that operate only at low temperature (<100 °C) can lead to some disadvantages in PEMFC systems, such as a low impurity tolerance and slow kinetics. To overcome the above problems, this study introduces a highly durable composite membrane with an inorganic filler for a high-temperature proton exchange membrane fuel cell (HT-PEMFC) applications under anhydrous conditions. In this work, polybenzimidazole (PBI) is used as a polymer electrolyte membrane with the addition of a sulfonated graphene oxide (SGO) inorganic filler. The amount of SGO filler was varied (0.5–6 wt.%) to study its influence on proton conductivity at elevated temperature, mechanical stability as well as phosphoric acid doping level. In particular, PBI-SGO composite membranes exhibited higher the level of acid dopant and proton conductivities than those of the pure PBI membranes. The PBI-SGO 2 wt.% composite membrane displayed the highest proton conductivity, with a value of 9.142 mS cm−1 at 25 °C, and it increased to 29.30 mS cm−1 at 150 °C. The PBI-SGO 2 wt.% also displayed the maximum values in the acid doping level (11.63 mol of PA/PBI repeat unit) and mechanical stability (48.86 MPa) analyses. In the HT-PEMFC test, compared with a pristine PBI membrane, the maximum power density was increased by 40% with the use of a PBI composite membrane with 2 wt.% SGO. These results show that the PBI-SGO membrane has a great potential to be applied as an alternative membrane in HT-PEMFC applications, offering the possibility of improving impurity tolerance and kinetic reactions.

PEM fuel cells fed by hydrogen from ethanol dehydrogenation reaction: Unveiling the poisoning mechanisms of the by-products

This work investigates the influence of hydrogen contaminated with the main by-products of the ethanol dehydrogenation reaction, i.e. ethyl acetate, acetaldehyde and unreacted ethanol, on the anode performance of a proton exchange membrane fuel cell employing different catalysts, aiming at understanding and minimizing the efficiency losses caused by these molecules. Pt-W/C and Pt-Sn/C catalysts were investigated, having Pt/C as reference, which were chosen due their ability to oxidize small organic molecules without breaking of CC bonds and without producing strong poisoning intermediates (i.e. less prone to have its active sites blocked by side reactions). Results evidence that anode catalysts that presents lower activity for small organic molecules oxidation and/or weaker reactant adsorption, which is the case of Pt-Sn/C, are best suited for PEMFC systems directly fed by hydrogen from ethanol dehydrogenation reaction. It is also found that crossover of the considered by-products from the anode towards the cathode also has a major impact on fuel cell efficiency losses.

Simplified anode architecture for PEMFC systems based on alternative fuel feeding: Experimental characterization and optimization for automotive applications

The need to reduce PEMFC systems cost as well as to increase their durability is crucial for their integration in various applications and especially for transport applications. A new simplified architecture of the anode circuit called Alternating Fuel Feeding (AFF) offers to reduce the development costs. Requiring a new stack concept, it combines the simplicity of Dead-End Anode (DEA) with the operation advantages of the hydrogen recirculation. The three architectures (DEA, recirculation and AFF) are compared in terms of performance on a 5-kW test bench in automotive conditions, through a sensitivity analysis. A gain of 17% on the system efficiency is observed when switching from DEA to AFF. Moreover, similar performances are obtained both for AFF and for recirculation after an accurate optimization of the AFF tuning parameters. Based on DoE data, a gain of 25% on the weight of the anodic line has been identified compared to pulsed ejector architecture and 43% with the classic recirculation architecture with blower only (Miraï).

Sensor FDD based FTC D esign for Time D elay PEMFC S ystems

An FTC design based on sensor FDD is presented for time-delay PEMFC systems with disturbances and uncertainties. A robust fault detection observer with a fault diagnosis technique is used. The Lyapunov principle derives the adaptive law and estimates sensor fault. A scheme based on FDD adaptive algorithm is derived to obtain fault in the sensor. The PEMFC systems simulations show the utility of the algorithm. Time-delays are considered in deriving both adaptive observer and FTC algorithm which is not incorporated in previous works on PEMFC systems. The simulated results can estimate the fault and validate the FTC design.

Robust fault diagnosis and fault tolerant control for PEMFC system based on an augmented LPV observer

In order to improve the safety and reliability of proton exchange membrane fuel cell system, this paper proposes a novel robust fault observer for the fault diagnosis and reconstruction of the PEMFC air management system. First, considering the complexity and large computation of the nonlinear PEMFC system, a linear parameter-varying (LPV) model is introduced to describe the system behavior and reduce the computation cost. Then, an augmented state observer based on the LPV model is proposed for simultaneously estimating the internal states and component faults. The robustness is guaranteed by taking the system disturbances and measurement noises into consideration when designing the observer gain. The observer design is transformed into a process of solving a set of linear inequality matrices. According to the results, the augmented robust observer can accurately estimate the system states and faults under different conditions. Moreover, to realize the fault tolerant control of the air supply, the oxygen stoichiometry estimator is designed taking consideration of system fault information and a corresponding controller is employed for air compressor voltage following the net power maximization strategy.

Long term durability test of open-cathode fuel cell system under actual operating conditions

Proton exchange membrane fuel cells are promising energy conversion solutions for both stationary and transportation applications. However, for the latter application, durability still needs to be improved in order to compete with internal combustion engine. Therefore, many researches have been carried out to improve their design, materials, reliability and energy management. A good understanding of the degradation mechanisms is one of the keys to a better durability. However, these degradation mechanisms are not yet fully understood. The purpose of this paper is to present a long term durability test performed on a commercial 1 kW open-cathode proton exchange membrane fuel cell system during more than 5000 h under specific operating conditions that aim at reproducing driving cycles, including electrical solicitations, idle, start-up, shutdown, and environmental temperature conditions. This study presents voltage, efficiency and electrochemical impedance spectroscopy measurements evolution all along the system operating duration. Results are used to investigate and understand effects of ambient temperature on the PEMFC system performance and degradation. Analyses could be used in further studies to improve energy management and extend the system durability.

Effects of Fuel Cell Operating Conditions on Proton Exchange Membrane Durability at Open‐Circuit Voltage

AbstractProton exchange membrane fuel cells (PEMFCs) continue to face cost and durability challenges which need to be addressed before their large scale commercialization. The PEM is an essential component of the fuel cell stack and its durability is thus a critical factor for the overall fuel cell reliability. Significant membrane degradation leads to the development of internal transfer leaks and cell short circuiting irreversibly affecting the fuel cell's functionality. In this study, perfluorosulfonic acid (PFSA) membranes were investigated for the effects of operating temperature and relative humidity on membrane durability using an open circuit voltage (OCV) accelerated stress test. The response surface methodology (RSM) was used to evaluate and optimize the effects of the operating temperature and humidity. As a result, the optimum fuel cell operational region was mapped and suggested as an alternative approach to maintain membrane durability without modifying membrane materials. The mapping could provide valuable guidelines for PEMFC designers and system engineers to optimize the operating conditions during idling to achieve a targeted membrane lifetime.